1. Field of the Invention
The present invention relates generally to sports equipment and, more particularly, to an improved shaft lock for interconnection between the handle and head of a lacrosse stick.
2. Description of the Background
In 1970, the introduction of double-wall, synthetic lacrosse heads revolutionized the game of lacrosse. In comparison to the traditional wooden single-wall heads, the synthetic heads imparted a lightness, maneuverability, and flexibility never-before experienced by lacrosse players. These performance advantages greatly enhanced players' skills such as throwing, catching, cradling, and scooping, and brought the sport of lacrosse to new levels of speed and excitement.
FIG. 1 illustrates a conventional molded-head lacrosse stick. As shown, a typical lacrosse stick includes a handle or shaft 20 (dashed lines) and a double-wall synthetic head 10. Head 10 includes a generally V-shaped frame having two sidewalls 14A, 14B joined by a socket 11 at the end narrow end of the “V” for receiving and seating the shaft 20. A transverse wall (or “scoop”) 16 joins the sidewalk 14A, 14B at the open end of the “V.” Webbing is woven between the sidewails 14A, 14B, scoop 16 and stop member 18 to form a pocket. The “double-wall” descriptor applied to the head 10 refers to the act that it has two sidewalls as opposed to the single sidewall found in traditional wooden lacrosse sticks in which the pocket is completed by a woven gut wall in place of a second, wooden sidewall. The shaft 20 joins the narrow end of the head 10 and is received in socket 11, which includes a stop member 18 defined by a closed-ended socket, and an outer throat 12 supported by extensions of the sidewalls. The throat 12 and stop member 18 are integrally joined to form one unitary socket 11. Typically, a screw or other fastener 22 placed through stop member 18 secures the shaft 20 to head 10. The traditional double-wall head 10 is a monolithic structure that is injection-molded from synthetic materials such as nylon, urethane and polycarbonate as known in the art.
FIG. 2 illustrates a conventional injection molded goalie head comprising the same components as a field player's lacrosse stick illustrated in FIG. 1 but having a different overall shape due to its generally larger dimensions.
The typical features of a lacrosse stick are shown generally in Tucker et al., U.S. Pat. No. 3,507,495, Crawford et al., U.S. Pat. No. 4,034,984, and Tucker et al., U.S. Pat. No. 5,566,947, which are all incorporated by reference herein.
The traditional double-wall synthetic head is an injection-molded, monolithic structure. Examples of suitable synthetic materials well known in the art include nylon, polypropylene (PP), polyethylene (PE), amorphous polar plastics (e.g., polycarbonate (PC)), polymethylmethacrylate (PMMA), polystyrene (PS), high impact polystyrene (HIPS), polyphenylene oxide (PPO), modified polyethylene terphthalate (PETG), acrylonitrile butadiene styrene (ABS), semicrystalline polar plastics (e.g., polyester PET and PBT), polyamide Nylon 6 and Nylon 66), urethane, polyketone, polybutylene terephalate, acetals (e.g., Delrin™ by DuPont), acrylic, acrylic-styrene-acrylonitrite (ASA), metallocene ethylene-propylene-diene terpolymer (EPDM) (e.g., Nordel™ by DuPont), and composites. When first introduced, these materials were clearly superior to wood, offering players improved handling and durability. For example, a lacrosse head constructed of DuPont™ ZYTEL ST 801 nylon resin is able to withstand the bending and harsh impacts inherent to competition far better than a traditional wooden stick. As another example, a polycarbonate head, though having a flexibility similar to wood, is more structurally durable than wood and much lighter and, therefore, easier to maneuver when attached to a handle.
Ever since the plastic head was incorporated on competition lacrosse sticks in the 1970s the plastic head has been attached to the handle with a simple screw connection, e.g., a “self-tapping” screw through the plastic head and handle (self-tapping screws cut their own threads).
The durability of that connection has long been an issue for several reasons. Repeatedly removing and re-assembling the components will eventually strip the hole and prevent stable assembly. In addition, the stresses on competition lacrosse sticks during play weakens the conventional connection inevitably to the point where the head sometimes loosens or even dislodges from the handle during play. Loosening/dislodgement can occur as the screw unscrews as a result of vibration, or as a result of the threads of the screw stripping from torque or other stress when no other forces are brought to bear to prevent these occurrences. The problem has grown acute due to the increasing use of lighter and thinner-walled handles. The thread engagement is often limited to two or fewer threads, causing excessive stress and instability of the head/handle connection. Stripping and loosening of the head/handle connection results. Further, when the handle is impacted, as frequently occurs during competitive play, the walls can compress or expand and the screw threads can strip. To combat these issues, players often resort to taping over the head/handle connection, but tape adds weight and is only a temporary fix at best. Finally, like all athletes, lacrosse players are bigger and stronger than they have ever been, so pressures on the screw connection are increasing from the increased torque applied by stronger players.
Previous efforts to solve the head/handle connection problem have been ineffective. For example, U.S. Pat. No. 8,052,549 to Sykora discloses a non-resilient plug-like insert with a magnet for insertion into the handle. But the Sykora insert adds excessive weight and does not remain securely in position. Other advertised inserts devised for this same purpose have been of different constructions from the device disclosed by the Applicant and due to those constructions fail to satisfy the need for a more robust interconnection for the handle and head of a lacrosse stick to avoid loosening and head rattle.
References in this application to “competitive play”, “competitive sticks” and the like refer to lacrosse games and sticks that are subject to a governing body set of rules and regulations, such as the NCAA for men's lacrosse, US Lacrosse for women's lacrosse, the National Federation of State High School Association for much of high school lacrosse and variations adopted by individual private school and recreational leagues. Such terms do not refer to articles that have some or all of the basic components of lacrosse sticks (e.g. STX “Fiddle STX”) but which due to their overall size, durability, etc. are not intended for use in competitive play.